Objectives: The aim of this study was to determine which surgical antibiotic prophylaxis (SAP) practices alter surgical site infection (SSI) risk.
Methods: Data were collected during a 7 year surveillance period (2001-07) from volunteer surgery wards participating in the INCISO Surveillance Network in Northern France. Main SAP practices, i.e. antibiotic choice, timing of first dose and total SAP duration, were evaluated and compliance checked based on French recommendations. The study focused on selected procedures in digestive, orthopaedic, gynaecological and cardiovascular surgery, for which standard SAP is recommended. Multilevel logistic regression analysis (a two-level random effect model) was carried out to identify SAP-, patient- and procedure-specific factors associated with SSI.
Results: Of 8029 patients who underwent the selected surgeries, 91.3% received SAP and 2.5% developed SSI. Among those receiving SAP, 83.3% received appropriate antibiotic agents and 76.6% had an optimal timing of administration. SAP duration was considered to be appropriate in 35.0%, too long (SAP unnecessarily prolonged) in 45.2% and too short (lack of intra-operative redosing when recommended) in 19.8%. In the multivariate analysis, a too-short SAP duration remained the only inappropriate practice associated with higher SSI risk (odds ratio = 1.8, 95% confidence interval: 1.14-2.81), after adjustment for surgery procedure group, the National Nosocomial Infections Surveillance System risk index, age and infection risk variability among hospitals. No significant relationships were observed between SSI and the other SAP parameters.
Conclusions: A too-short SAP duration was the most important SAP malpractice associated with an increased risk of SSI. Information directed at practitioners should be reinforced based on standard recommendations.